纽约警察站在时代华纳中心大楼附近,大楼因炸弹威胁被疏散后,在纽约曼哈顿区,纽约,美国,2018年12月6日。[照片/机构]纽约-星期四向美国数百所学校、企业和政府大楼发送的一系列炸弹威胁引发了搜救、疏散和恐惧-但没有爆炸迹象,当局说,恐慌似乎是一次粗暴的敲诈企图。全国各地的执法机构都驳回了这些威胁,称这些威胁意在造成混乱,迫使受援国汇款,但被认为是不可信的。有些电子邮件的主题是:“三思而后行”,它们是从一个伪造的电子邮件地址发送的。发信人声称在收件人的大楼里有一个同事在放置一枚小炸弹,阻止他引爆炸弹的唯一方法就是在线支付2万美元的比特币。”纽约市警察局反恐部门在推特上写道:“我们目前正在监测以电子方式发送到全市各地的多个炸弹威胁。目前,这些威胁也正在向全国各地的其他地方报告,这被认为是不可信的。”其他执法机构S还驳斥了这些威胁,这些威胁以一种让人联想到尼日利亚王子电子邮件骗局的波涛汹涌的风格写着。佛罗里达州棕榈滩县治安官办公室和爱达荷州博伊西市警方说,他们没有理由相信对这些地区的威胁是可信的。博伊西警方局长威廉·博恩斯说,其中一封邮件最后被过滤成垃圾邮件。联邦调查局表示,它正在协助处理这些威胁的执法机构。”和往常一样,我们鼓励公众保持警惕,并及时报告可能对公共安全构成威胁的可疑活动,”联邦调查局在一份声明中说。星期四的恐慌发生在两个月前,当时著名的民主党官员和CNN在曼哈顿的办公室被炸弹袭击。这起案件的嫌疑人塞萨尔·萨约克在等待审判的时候被关进了监狱。2015年,一封电邮炸弹威胁引发了美国两大公立学校系统的不同反应。洛杉矶的学校系统因受到大规模袭击的威胁而关闭,但纽约市官员很快将其视为一场恶作剧。在星期四的电子邮件之后,全国的一些学校提前关闭,其他学校被疏散或关闭。当局说,从俄罗斯向密苏里州特洛伊市圣路易斯东北约55英里(88公里)的一所学校发出的威胁电子邮件。炸弹威胁还促使伊利诺伊州奥罗拉市政厅、北卡罗莱纳州罗利市新闻与观察员办公室、亚特兰大郊区法院和底特律企业撤离。密歇根州警方发言人香农·班纳说:“全国性的公共和私人组织今天都报告收到了通过电子邮件发送的炸弹威胁。”宾州州立大学通过一条短信通知学生,告知他们对宾州州立大学主校区的六栋大楼和一个机场的威胁。在最新消息中,该校表示,这一威胁似乎是“国家恶作剧”的一部分。科罗拉多州哥伦比亚高中的官员星期四正在处理一种不同类型的炸弹威胁。在有人对学校发出炸弹威胁后,学生们被关在里面一整天。科罗拉多州杰斐逊县治安官办公室说,打电话的人声称在学校里放置了爆炸装置,并用枪藏在外面。警长发言人迈克.塔普林说,在哥伦拜恩没有发现任何东西,1999年有12名学生和一名教师被两名学生杀害。另外24所科罗拉多州的学校也被暂时停课,这意味着他们的门被锁上了,但随着威胁的调查,班级继续正常上课。AP
NYPD officers stand near the Time Warner Center Building after the building was evacuated due to a bomb threat, in the Manhattan borough of New York City, New York, U.S, Dec 6, 2018. [Photo/Agencies]

NEW YORK - A wave of bomb threats emailed Thursday to hundreds of schools, businesses and government buildings across the US triggered searches, evacuations and fear — but there were no signs of explosives, and authorities said the scare appeared to be a crude extortion attempt.

Law enforcement agencies across the country dismissed the threats, saying they were meant to cause disruption and compel recipients into sending money and were not considered credible.

Some of the emails had the subject line: "Think Twice." They were sent from a spoofed email address. The sender claimed to have had an associate plant a small bomb in the recipient's building and that the only way to stop him from setting it off was by making an online payment of $20,000 in Bitcoin.

"We are currently monitoring multiple bomb threats that have been sent electronically to various locations throughout the city," the New York City Police Department's counterterrorism unit tweeted. "These threats are also being reported to other locations nationwide & are NOT considered credible at this time."

Other law enforcement agencies also dismissed the threats, which were written in a choppy style reminiscent of the Nigerian prince email scam.

The Palm Beach County, Florida, sheriff's office and the Boise, Idaho, police said they had no reason to believe that threats made to locations in those areas were credible. One of the emails wound up in a spam filter, Boise Police Chief William Bones said.

The FBI said it is assisting law enforcement agencies that are dealing with the threats.

"As always, we encourage the public to remain vigilant and to promptly report suspicious activities which could represent a threat to public safety," the FBI said in a statement.

Thursday's scare came less than two months after prominent Democratic officials and CNN's Manhattan offices were targeted with package bombs. The suspect in that case, Cesar Sayoc, is in jail while awaiting trial.

In 2015, an emailed bomb threat prompted different reactions from the nation's two largest public school systems. The Los Angeles school system closed down under threat of a mass attack, but New York City officials quickly saw it as a hoax.

In the wake of Thursday's emails, some schools across the country closed early and others were evacuated or placed on lockdown. Authorities said a threat emailed to a school in Troy, Missouri, about 55 miles (88 kilometers) northeast of St. Louis, was sent from Russia.

The bomb threats also prompted evacuations at city hall in Aurora, Illinois, the offices of the News & Observer in Raleigh, North Carolina, a suburban Atlanta courthouse and businesses in Detroit.

"Organizations nationwide, both public and private, have reported receiving emailed bomb threats today," Michigan State Police spokeswoman Shannon Banner said. "They are not targeted toward any one specific sector."

Penn State University notified students via a text alert about threats to a half-dozen buildings and an airport on its main campus in State College, Pennsylvania. In an update, the school said the threat appeared to be part of a "national hoax."

Officials at Columbine High School in Colorado were dealing Thursday with a bomb threat of a different sort. Students were being kept inside for the rest of the school day after someone called in a bomb threat against the school.

The Jefferson County, Colorado, Sheriff's Office said the caller claimed to have placed explosive devices in the school and to be hiding outside with a gun.

Sheriff's spokesman Mike Taplin said nothing was found at Columbine, where 12 students and a teacher were killed by two students in 1999.

Two dozen other Colorado schools were also temporarily placed on lockout, meaning their doors were locked but classes continued normally, as the threat was investigated.

AP